SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8ec65cdc589eea5a81f69dfa2179a6e80b6c9f05d1ae36adce6a48214fa7755' 
  AND token = 'PS71dlUvXxry5nbCaZM14XPmtPaw4PxMEB0S6/W3UWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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