SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15d18c071cb1dd2da0ca49a40b471c446decab32e685aa7611e25c32bfab1b58' 
  AND token = 'Fixtwm050jY+kccP3uBdHBePeyqFwofZNQjHzJUOmew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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