SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f536da00f12036fd3d1a8e3034201b2b34324d6212d87fc429787cc16aaac71a' 
  AND token = 'Tj0EyabJ18X5PDJTAm0o3flYMOGGMMOAiqIRlwJWlXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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