SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f5bd12b8a0527320ed058989c7c4bda05604955992c984997c5d415cfb8cff3' 
  AND token = 'pg+bEYJy6giXTgxFEAzmaoePs+UFjMB+NQU1107c8Lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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