SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2602adbfba64a36784da6024a78968f0853e63fdf59948c6c8f9a80142d034d' 
  AND token = 'vlvtfkwpBFKmW3QRr0zLs9NFj2P01R8cxcdXbDbW3Is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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