SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd900dfa5483c17473d91374e201bd937f08e3966fe8f0931ff861becc2c3f3a4' 
  AND token = 'CIkzMRMIj/bgJYizWmQgUfz43Vjr2HLtu+p7KvZ2DUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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