SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a36f0f6b5dd4d0d2a550042ca165d697d538b18dee0bde827337aeedcb7cbaa' 
  AND token = 'U+dmieGVTfYeAcvVbEMfxvZXUkTOycFAXG+Gya5W1tA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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