SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20861f87b179a80b47b08aa951a1d703f1a6a818cfceeff1a4c1ffe38aa5fc49' 
  AND token = 'xmIbv8EPaaHj8rOzsNIIlE2CZWSFziQbhGGsdoTAT1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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