SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a1d50804fd5285c4c2cfcb4c63ef463c49d2014f85843f9abc2058f0a592c81' 
  AND token = 'T/GkEzHCtJd1god3SF4JEr3uW5+iEMyQ3Fyhe9jiyDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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