SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58b698856fbe21d307a126414eb41bd82b7fbbbdea6257a0949876569a83e79c' 
  AND token = 'Y0OmRfdh/ycDJkJAjQr11uuUQq839D0/CCgEpfxk+5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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