SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '890cf1221feb1743fefb99ddbc823b512f2fdc579b4db3dc3958e416815d0bed' 
  AND token = 'IN/qOk5RoNr76CoNSVhBrQhp8D2NIH+NBMHUvxR0OIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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