SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '499d0757bb175def18b82c8c69f2bbb563135f14f8383224498b45e072d1d94e' 
  AND token = 'UQj6Mb/epYvy4yaUBidkRpGkPt4c8HhhIMtNuZH/pfY=' 
  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"
    }
  }
}