SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f971507f38079c6adc24858241a2b1d533679e9b3e61ec2b9544cfe20e10ac84' 
  AND token = 'Ad5ZRdpN42uN4jguAEssJyOBUxMT4HqwRhLlTCAkYG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}