SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a395b7a82c9761417ef312c2f3a6f67236dcfe39f1912d0956b11bd3a9a7694' 
  AND token = '7VaG1gSYYmFGUpQcsXSyxo0byWmCKGYtjIz5MJ5AhlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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