SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '835f46f5e064ccd22ed9d2999b1d415d6770acec57c316a493108c485fa936c2' 
  AND token = '0EbiVwjoT1o5fzwa3jKW8zCPlYdfxqTMHH17bCjho2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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