SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9fddde396d0bbe2a498cc19e67605f6e453315f25c04e9e4d151f209f60e441a' 
  AND token = 'hX72hhEMv80QqutXRjoFFZIGMQyRTFi7vOx+wEtYm5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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