SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38cbe210aca3c895e67cb4181062b2f82998d4235088aa6a7691885aa1482638' 
  AND token = 'fZdRRym94yLynbeUC1HIL/JdQ2eK+jR9BxwoVHnfSds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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