SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c385c4822db663bc2070801659dd123124ca502700b83cd99650b333f144f70a' 
  AND token = 'Xh1DoksjiMeR61IsRQO5c5sOi+ERweXgS19wIClFVhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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