SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eabfe6f20929f6da42ce6c1319742794cdd98a69dc89f44d7cfccb67caaaaa4f' 
  AND token = 'a9VwJoBsMm/g4XKFBsnFRo6+GzseKiG/7SPNSKc9nk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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