SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b60156eb58ccb3badbe897e6cb6db6e21258649ef2dd0afccbdb4a53d1edc4a2' 
  AND token = '6FLMJm219kBIbl7+lO1PR59oLywxwaAFgwZ5AimHYFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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