SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37418860a830408a8c4d0c8a7074e6a1a48f381200aa8446735852d275ffa763' 
  AND token = 'QmBwTSg569umsSNwOkvUkCgKYU3vfWd9DCo9yp0hGHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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