SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ada89d6365959997452422f68fbc839127fa847cd1363bb641ffaf0893d2194' 
  AND token = 'DxDUZPugflYuF2jgNjYnn+egBl/Ari87j672upZPjCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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