SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe639d3b2a6e07ac3bd18ecaaaca075183100cdca08b975a330f0a4f163059da' 
  AND token = '3MYRbpzSYyRBbgrAVuXTq/LA5iVcqr7of8CUiRU4XZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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