SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ffb42de954680e4849a9e56ad98db97bb93310d73d01af6c5226ba4affbdd05' 
  AND token = '0Gnd22S0UJVzxdKT88ndu1oAARddXSlPzlhCWyos6Nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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