SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9d349d8a99327ea6fb71df2e13d33495ef35f183e1ac1379d0e1eb5263f3599' 
  AND token = '8WePL++zi/JUOMY4biMvnPHAGjCCGy3Qq1CgJb+mMQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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