SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b513ae55318d38231e2f1bbee00682d9f414e89d2db068dea5286f5e7e7c47c1' 
  AND token = 'b282pIl3JnfEKar0odukodu4XTKzo4XwjKTWUxJ2lIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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