SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c73d3e411c0d85ababa0dc87639b723816decae00bd8082eaf2fee4fcd55f8b0' 
  AND token = 'JxGzChp2pqLXOyspQwqqALFuCR3UT7/nJryxsT1k9y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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