SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18ed9b07006eeb2543d94676e5aa3c1b8ebe6761be06a6ff82c126401a58cc44' 
  AND token = 'I1KnkWDtq5oTSSi1pl2ZVqR3XqSC63+9SDSrNu4DYLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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