SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fafdc19471684609ec027cd0e7fc38a386765fd4f1383820df100174f29b25e9' 
  AND token = 'NC7E5/LbGLpaePlaO1s6IMiAXdHBxPgWgK+KfxP4NZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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