SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29b712913795cbdfbda127baf2fdab717210399bad0ab9b2825e0d78a10f5dda' 
  AND token = 'St1/8WiBOSNSgWhnoDCk3pxhZihTHQjX6kHV2sH6zNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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