SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fac57b500d3853acbcf28a92396897553644a74d8ce6d05d6a9ed64daaeb7b4' 
  AND token = 'TxdYAuZG9xVqmXTCPyknidL+xWFlktvELYxCQFDSm+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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