SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f5fb9ba621976c462fc630925194297f488358f69b2d25d6f9e247d2aa5704e' 
  AND token = 'At0rWJgrgIK+wRrZOCHIqEBsBrTqVVgllw3opEuuJ60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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