SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4c9d57c320fc488cd00a98759fb915598cbab891c1ebeafd0b693534c1d1e4d' 
  AND token = 'HAbnL2R5gm8HP/qRJWvd+dxMM7KhhGwDbnjArpddoNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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