SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55d2b4d35895e4d189d248fc32fb2a938126c31d9ec6c8aa1c5eb716ef84ac27' 
  AND token = '2MgXyKxg376p/vhkKYCx3KljjQY7pVo61CirfUsTV6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}