SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3ef1cbce1b6e8d54d00fa1b180355998494efe270e841b66454b707a869fe00' 
  AND token = 'fLlAvmunut5gMptkmR4pRdL2dShKh5vY78QNgjVEtF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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