SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caa35feb440edab7aa7dcc1cc57fcd0ecde1f04ee7571f3c290c211a241ee43c' 
  AND token = 'Q325B7Muxpbfuvqjrs/T43178RZepxUAtxk5N3bdLos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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