SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '277a79dbe39da815ab97442d50bebd8774333da56bf240db37561a6d305262a2' 
  AND token = 'hU2gofrvYnMlSu0s8dLPFhSznP4aAw3FgFTyqzYpfiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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