SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '815115c6cd600e66395b148ba7f121d68d5bf43d6b3609306e1d5cf2a5810c9c' 
  AND token = 'HjjcrKq62Cyv6QfoDzo33OSZm5486KuOFE5HwzmkkaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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