SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cec12dabd6352bfdb0666f656514322ff88c141154e125e52069fd561a17c3d9' 
  AND token = 'PyFiErSw04yTlD8dryQ3Ci579Wk20ksH2u+6JaEvMho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}