SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef5dc49c3cc5a3724ad97a9eda4e2fc2c192d43cd4dc0b953f5eec110084d865' 
  AND token = 'gXV3zu54lmZRBkqT175tOJ/LCGsYKZuExSHkghOtGOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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