SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecff7172b2883e2938b88176b6480d18352dc1194d745490b5d331d7c97d10f7' 
  AND token = 'YknDlHK4DOqqdTe90xDr61N5U7eDhSpcl+cqmjA5ZfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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