SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6643d32dec7b2bd727b58f2e336d56148b151cb0db8c7c120ba19b5d39165c5e' 
  AND token = 'fA/xoJSTSw1KZGz4TSvKxFZhRdBLOMwDQTsjBc2+tTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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