SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa29ad320769108f06760c878c1e18d01f851edd10695394f7ab409746fa6e83' 
  AND token = '3aDeUlttgL3q4nPunWCwBYRcqAfyfnJXCKOrS903htE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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