SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b5331191caafb89b30dfdc2cc35b99582851203061824d56ebbe3a04d86a540' 
  AND token = 'AVZzGfun2Bpm+03vaGS56FHghEcf4sS1iJAVvAhUrMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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