SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a6c6f40ca03a50ca25b103804ea7eb2ef74dd3cda5280cce1dc73a061ec8c72' 
  AND token = 'gL5cPf41KFNwUEFeXtztnjjZTnQ59XN/o6STB8Hv+dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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