SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b91c29033e5895a15bd7150ac56e47ecf083692c42ce15969d6046ff90f39804' 
  AND token = '5gxuIi2WnVyYMpkYtNZ3Teg7zQ3/JPI9odm8o0/82lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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