SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8a8c362d87b182d92e81196f57f11310135c4caa184fdb36aa9d6f904575a1d' 
  AND token = 'tOOUseyCAyKAwQVKvYgHsjumjIvP0Trb2rCvVI3pwXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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