SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b197ef5a0f56e272855527c3f5cf4e4a9c4634dffee8b0c5b56b4ea4ad6cdd01' 
  AND token = 'nzNYy/s5LgoGoxBuz8SGCxqxZt+mKr26FjDIgXzIwd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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