SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74897b5004ab391d8d8bd98a7355812e4c06357c3c956084fa1ef352c1e9abd3' 
  AND token = 'DXKtQg+2LuuWQPAZnjGxxKuG5bTSlv8lIpgzppP1sAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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