SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f302bc36b3c49d6494fde3acdab3748f46692760944ae45d3123557d0d073c4' 
  AND token = 'pEORnfdOGkxINBuDqBqWbJFm7wMN3IHHn+uI64iPQ8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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