SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab5c28038a4790c475098db83f380f512960cc446c804e654dd82dc7c7b57589' 
  AND token = 'DNf1ivmXMh+jbTknwwA/YkhgtzgBPDAD7juYueR1s1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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