SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36936c9cab4b98fbd0620382c15207f4700b4d820713bedef6787cf6858ff375' 
  AND token = '8x+/N3gYSD/HsZbYm6LNfXvsw/Nsqb/uT8R/B+EoVKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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