SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b42b3690455e682d8c9ef8e95879432cfb67f22d8222f40a5f219c48efc62808' 
  AND token = 'zG8tONw7oeD5vVW0KHL7Kl/+Z1leySTQUEZs+s8vHZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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