SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77f3534936c3e9955995c94341f11e05a431cf708034859c1d80bf7de46dbd72' 
  AND token = 'TroyMh1hOC0122uSLMuQ2OYyz2VX1IV9cd4+AV2i2O0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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