SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d4f680bf9be1953836b75014534f6e2b86cb313fb2a8bc888e0b4f725dc029b' 
  AND token = 'mZM0d30shB3BoYMQeCIkqgSWNXdJluvDDY93L5gknio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}