SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef5194fad8db4caa6883fd924d71cd7f9348f8d8346c2a55efee2d36460d2526' 
  AND token = 'rVcRm8d1yU5bpPSgrnLLhD6jYZzluio+2YQc96L5Zx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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