SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f84883c7e438a5efd6bd518b7cf582137fd65565492f13a3657ef8d05f8a661' 
  AND token = 'j6mVUEGA9UhqsaJeB9Ld9zTCSbAWfV/KfIRZ4R3UXhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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