SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc0fc0ad64e6ceda699cff9bf05cff0b0cffc15fa0a2db21c6f0ce6ddc51ed71' 
  AND token = 'TMJRRw9sCuNvxIEcVgCmrXHGjG1mkkMJLak64uVrzMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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