SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b19e7c128e82e74d1fb192646ec25090e6a43d64ff04c9a2e8df8e54490cb711' 
  AND token = 'PZDMixur10W7zwjW20X2Kt3l+HisuiLQ8x/qqFgZz/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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