SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '517a0b54fc1cfee0910481b609151c247cc42fefc47ceec7243601af85bddc93' 
  AND token = 'E9Hnrv9//BeE8qLHT1ShOHNNTEeBbqhpaaG9PsMuTsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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