SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c331ab01da4ee892daf0935d9940db55f9feecf4019d2e93a2a1f887bc67bc16' 
  AND token = 'aAvABTsmYV8Kb610zjinA4EhmEF6+tdMLrAiWog3s1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}