SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cce2849ef9cffa1725e3598115f9a03bf2657bb344aa5f19563d5237898cf1e7' 
  AND token = 'ZMCF1cD8VeStQLfoSaSdHedEC8CaKDwYCm2uUjiSFHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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