SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49775912eb2c112e3f5d22cc5cbf14667d6aff50ab5d231b61027d3bb6d4eb5e' 
  AND token = '3wjLNhTIIYpqBZ9UJQxYviBvm2XTlS6Q+Urk/vRFGNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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