SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e13a67035618b9de4a0e7b58330d256cc595a6548aa6823f6f1822c4938321f3' 
  AND token = 'RdYUgILTBhY98puJVAvuBSuDxj2XMKw4TNtA9aTfVvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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