SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2781eb31e8f7f924ac5cb0eaced1c1448ab951d0fd2850ca451370e877c435d' 
  AND token = 'iwjVGfm/rgwmETuicbVnDqnJtI1jAiXMoEr/UyUU8Hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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