SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55bed46e04676e20f7c7a18d61113b9b3aad866ef6a05bfbcba0b4d8504dd5e5' 
  AND token = 'eCOMNnlYFg6jHpWmoF8XRgrvRCWs+UzscJxG2T6JAuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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