SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53fa55002930d0f2a50e7a13afcb993048be5cede7e98290cfe389f54484c932' 
  AND token = 'NdYDiPy3bLGvTDHJrAxnku6HEUP9XJ1qgxcGZNLKRJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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