SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0bb1b1110287945852d710b55de22b1471852962f3bf4063cedb8856f02326d' 
  AND token = '2/5wpWJ4xEpkd9jnFb5l3DJSmQvHo395mOP2nZESuB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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