SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73968373a7a832e18ea340b2156be079adbd7867aa8104bb40c2192d1d41b2c2' 
  AND token = 'w2VVPSlpjG283aPn+bgs4lOQtYfKsvsZyJ/eKEPPXcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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