SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46293714a8cd00e6c55c1fb92f1d58b2452b08d21defee2d1c8ee205574a44cb' 
  AND token = 'ZAroqMRhRCbUahzAa867LS9ULQZmx9L2jv79wc7qeRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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