SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bb2cff2e11acccbb975f17c9891e64bc7d218da5078e4d0076a5c083771a2f4' 
  AND token = 'sBKgmv6DA2gXuwKvse+R8kBPNCJNqPjhU1uh74/6/Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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