SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d473bfce79ed9cce9d57241e57582a7f794149a5d6ceff2225865d68ab52c22' 
  AND token = 'dEVXuUKm1kf1TW00ZrTFwmmmM3Nkzoc+Kc6M5FaGiMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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