SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1c1fd80dd3c6e54bad11fa0de3c5233437aa786f863da486e478451959427d3' 
  AND token = 'NLRNyJKA2bh/MspRQnGQE7YlxPV3QBC5qJJukjLwvHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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