SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c58e3069edfcea450079e52e3dcaffdd143cf54c7dd78baadb847fb69311346' 
  AND token = 'fn1rTYAv9w+FDwLzzVX28TTAh9etZZlO+OQfRJqrdqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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