SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90b40604307a358d68cba5af053a73953f03ed12514379108bdd1c5758e8b46b' 
  AND token = 'i8i92eVP58dQfNA2mfBZpUjZukE9hWEijKLSMex7AlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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